It's almost unbelievable, considering how fast the company climbed the music retail charts. Ars Technica is reporting that Apple has ascended to the top, surpassing Wal-Mart for the first time ever, according to an NPD MusicWatch Survey for the month January contained in an internal Apple e-mail which was leaked to Ars Technica:

"The fact that a digital-only retailer has ascended to the top of the sales charts is not unexpected, but it does demonstrate just how much the music landscape has changed since the beginning of the decade. The NPD Group has been tracking a sharp increase in digital downloads over the past several months as physical sales dry up. According to NPD's research, 48 percent of US teens didn't buy a single CD in 2007, compared to 38 percent in 2006."

The report said that there is a "dark side" to Apple's ascension, since buying patterns for digital downloads are different—customers are far more likely to cherry pick a favorite track or two from an album than purchase the whole thing. "In contrast, brick-and-mortar sales are predominantly high-margin CDs. For 2007, that translated into a 10 percent decline in overall music spending according to the NPD Group, and it's a trend that's expected to continue for the foreseeable future."

Just nine months ago, Apple had assumed the number three spot.